BLOG

There is growing evidence that the food we eat affects not only our physical health, but also has a significant impact on our mental health as well. Specifically, studies indicate that consuming a poor quality diet may lead to structural and functional changes in the brain that are associated with depression and anxiety.

“…strong link between unhealthy diets and changes in neurotransmitters…”

A recent study conducted by researchers at the University of Reading, Roehampton University, Friesland Campina (Netherlands), and Kings College London and published in Nutritional Neuroscience further explored this association. The researchers found a strong link between unhealthy diets and changes in neurotransmitters and grey matter volume in the brain.

Those who consumed a low quality diet, defined as poor adherence to a Mediterranean style diet, showed reduced grey matter volume. Reduced gray matter volume (GMV) in the brain has been associated with numerous mental health conditions. Interestingly, the researchers found the changes in GMV predominantly in the frontal part of the brain, which is specifically correlated with depression and anxiety as well as rumination, a common symptom of many mental health conditions.

“The gut microbiome, composed of trillions of microorganisms living in our digestive system, is a key player in this connection.”

As discussed many times in the Mind Gut Connection Newsletter, the brain gut connection is a bidirectional communication system between the gastrointestinal tract and the central nervous system, which plays a crucial role in regulating mood, cognition, and behavior. The gut microbiome, composed of trillions of microorganisms living in our digestive system, is a key player in this connection.

A poor quality diet, typically high in ultra processed foods, excessive amounts of saturated fats and refined sugars, can disrupt the balance of the gut microbiome, leading to dysbiosis. Dysbiosis can then lead to a compromised gut barrier, commonly known as “leaky gut.” When this occurs, inflammatory cytokines and other inflammatory molecules can enter the bloodstream, triggering an inflammatory response that may extend to the brain.

If inflammatory molecules cross the blood-brain barrier, they can cause neuroinflammation. This state of persistent low-grade inflammation in the brain has been linked to alterations in neurotransmitter systems, particularly those involving serotonin and dopamine, key regulators of mood and emotion, as well as reduced gamma aminobutyric acid (GABA) and elevated glutamate.

“… inflammation can impair neuroplasticity, the brain’s ability to form new neural connections and adapt to changes.”

Moreover, inflammation can impair neuroplasticity, the brain’s ability to form new neural connections and adapt to changes. Reduced neuroplasticity is associated with cognitive decline and an increased risk of developing mental health disorders. Studies have shown that individuals with depression often exhibit decreased volume in brain regions crucial for emotional regulation, such as the hippocampus and prefrontal cortex.

“Oxidative stress can damage brain cells, disrupting the central nervous system…”

A diet lacking in essential nutrients and antioxidants can also lead to increased oxidative stress in the brain. This occurs when there’s an imbalance between the production of harmful free radicals and the body’s ability to neutralize them. Oxidative stress can damage brain cells, disrupting the central nervous system and neurotransmitter function, and potentially contributing to the development of depression and anxiety.

“…the relationship between poor diet, brain changes, and mental health is often bidirectional.”

It is important to note that the relationship between poor diet, brain changes, and mental health is often bidirectional. Depression and anxiety can lead to poor dietary choices, creating a vicious cycle that exacerbates both physical and mental health problems.
While diet is just one of many factors influencing mental well-being, it represents a modifiable risk factor that individuals can address to potentially improve their mental health outcomes. Adopting a balanced, nutrient-rich diet is likely able to positively influence brain structure and function. A health promoting diet along with other lifestyle factors such as daily exercise, stress management and adequate sleep is likely to play a significant role in the prevention and management of depression and anxiety disorders.